By the end of this Instructable you will be able to successfully create your own potato launcher. Potato launchers are a fun project to create and can be finished in a couple of hours.
Step 1: Required Materials
In order to make a potato launcher you will need all of the required parts. These can be purchased from your local hardware store. The approximate cost of the supplies needed for the potato gun is around $30. They are as follows:
1. 3" x 2' PVC Pipe
2. 1.5" x 5' PVC Pipe
3" to 1.5" Reducer
4. 3" PVC Screw on Cap
5. A Lighter
6. 2 Screws
7. A Can of Hairspray
8. Electrical Tape
9. PVC Primer
10. PVC Cement
11. A Saw
12. Potatoes, or projectile of choice
13. Wooden Dowel
14. Screw Driver/Drill
Step 2: Prime the PVC
In order to attach a piece of PVC to another piece of PVC both parts need to be properly prepared. This can be done with PVC primer and PVC Cement. The primer creates a clean surface free of impurities which will maximize the effectiveness of the cement. The cement is then applied to the primed surface.
Step 3: Fuel Source
This is the 3" diameter pipe with the 3" to 1.5" reducer on it. This will eventually be where the hair spray or other fuel source is collected. To create this part prime one end of the 3" diameter PVC pipe and let dry for about one minute. Once primed apply the cement to the same end. Lastly slide the 3" to 1.5" reducer on to the primed and cemented end. Next prime the other end of the 3" diameter pipe. Once primed again cement this end. Once the other end is prepared attach the 3" PVC screw cap. Once both ends of the 3" pipe have had the reducer and cap attached let the cement dry.
Step 4: Primed and Cemented End
This is what a properly primed and cemented surface looks like. The primer is purple and the cement is a clear coating on top of it. The PVC screw on cap can now be attached to the end and allowed to dry. Make sure to follow the instructions for the particular type of primer and cement you use as the drying times may vary. You can see the 3" to 1.5" reducer has already been cemented on to the other end.
Step 5: The Igniter
Disassemble the lighter. Make sure you are using a lighter like the one shown in the materials photo. It must have a long ignition tip. Remove the ignition piece, it has two long wires coming out of it. This will be the source of the spark to ignite the hairspray in the potato launcher.
Step 6: Attaching the Lighter to the Potato Launcher
Attach each wire coming out of the lighter to separate screws. Screw each screw into the 3 inch diameter pvc tube roughly in the middle of the pipe. Make sure the screw tips are roughly 1/4 of an inch apart. When the lighter is initiated this will produce a spark between the two screws and ignite the hairspray and air mixture. You may want to check that the lighter and the wires are in fact created a spark inside the pipe. Without a spark being creating there is no igniting the fuel. CAUTION! When checking that you are creating a spark make sure there is no hairspray or any other fuel source inside or near you and the pipe as you could create an unintended explosion.
Step 7: Electrical Tape
Electrical tape can be used to insulate electrical items. This keeps them safe as well as working properly. Electrical tape is essential to the upcoming steps.
Step 8: Applying the Electrical Tape
Wrap the electrical tape around the wires and the screws of the ignition system. This will hold them firmly in place. Also it will reduce the risk of an accidental shock from the lighter. Also tape the lighter source down but leave the button exposed so it can be pressed when the potato launcher is ready to be fired.
Step 9: Applying the Firing Barrel
Prime the end of the 5 foot 1.5 inch diameter PVC pipe. Also prime the end of the 3 inch to 1.5 inch reducer. Apply cement to the primed section of the 5 foot tube. Insert the tube into the 3 inch to 1.5 inch reducer. Again allow this to dry as long as the cement instructions specify.
Step 10: Ready, Aim, Fire
Once all the cement has fully dried you are now ready to fire the potato launcher. Remember safety is always the number one priority. Tips to ensure safety include many things. First make sure the previous steps were followed properly and all the PVC pipe connections are tight. Always were safety glasses when firing. Also when firing be sure that no one is in the firing path or behind the cap end. The potato will be a fast moving projectile and the cap end could come loose and anyone behind it could be hit or burnt. Lastly be aware that the range for this can exceed 100 feet. Large clear spaces such as fields are recommended for shooting areas. Next is shooting instructions and tips. First put a potato in the 1.5" diameter PVC Pipe. To push it down a wooden dowel is suggested. Make sure the potato is nice and tight as far down the pipe as you can get it. Do not push it past the reducer into the larger pipe as it will not fire properly. Next is adding the fuel to the potato launcher. You will need to unscrew the PVC cap end. Spray 3-4 short bursts of hair spray into the cap end of the launcher. Once the fuel is added immediately put the cap back on to hold the fuel in the launcher and not let any escape. CAUTION! The launcher is now fully loaded and prepped and can go off. Make sure the launcher is not pointed at anyone as there is not a safety button. When properly aimed and everyone is clear hold on tight. The explosion can cause a lot of force and recoil. When ready click the ignition switch. The launcher should fire. If the launcher did not fire there are a couple issues that could of happened. Please troubleshoot these suggestions to diagnose and fix the issue. Try clicking the ignition switch a couple more times as the fuel may not of ignited. Second try spraying more hair spray into the fuel chamber. The fuel may have escaped. Third, check that the switch is creating a spark(check this with no fuel present). Lastly if it still won't fire there must be a leak and the interfaces of the PVC components isn't properly sealed. Try finding and fixing the leak or building a new gun. Once fired repeat the processes from this step to fire more rounds of potatoes.